The broad, long-term objective of the proposed research is to find the causes of severe premenstrual mood and behavior changes, facilitate diagnosis, and speed effective treatment to women seeking help for related disorders. For decades scientists have worked to identify characteristics of the ovarian axis that are associated with premenstrual disorders. Now, results from state-of-the-art endocrine research, the body of knowledge about premenstrual dysphoric disorder (PMDD), and our pilot study converge to suggest that inhibin B, a new marker of ovarian function, may be a biomarker of PMDD. The Specific Aims are to explore (1) the relationship of inhibin B and PMDD; and (2) to determine whether inhibin B differentiates women with and without PMDD after potential confounders are taken into account (the Aberrant Inhibin B Model). Hypotheses will be examined in a sample of 18 to 53-year-old Hispanic, Black, or White menstruating women with or without PMDD (N = 102). To diagnose PMDD according to DSM criteria, participants will rate symptoms and functioning daily for two menstrual cycles, and complete physical and psychiatric evaluations. In each cycle, participants will give blood samples every 3 days after the onset of menstruation until ovulation occurs as determined by home urinary luteinizing hormone test kits. Inhibin B levels will be measured in serum using ELISA. If inhibin B is a marker of PMDD, this may provide clues to the mechanisms of the disorder, premenstrual exacerbations of other conditions, and emotional reactivity in general. Laboratory studies of inhibin B already have been translated into practice aiding diagnosis of various reproductive conditions. Results of this and subsequent studies may facilitate diagnosis of PMDD. New medications targeting endocrine risk factors for premenstrual disorders ultimately may be discovered. The medications may be more efficacious, and more acceptable to women not wanting antidepressants. Data from minorities and perimenopausal women should help scientists address health disparities. Premenstrual dysphoric disorder (PMDD) is one of the most common conditions affecting reproductive age women having a high impact on personal well-being and professional productivity. This study explores the relationship of inhibin B, a new marker of ovarian function, and PMDD. Results are expected to provide clues to the cause of PMDD, facilitate the now burdensome diagnostic process, and lead to new treatments. [unreadable] [unreadable] [unreadable]